Ash-discharge device for furnaces



H STEHMANN.

ASH DISCHARGE DEVICE FOR FURNACES.

APPLICATION FILED SEPT. I8, 1919.

Patented Jan. 31, 1922.

UNITE sures FATE HARRY STEHMANN', or BEBLIN-HoHENsHonHAUsnN, GERMANY,

1 ASH-:DISCHARGE DEVICE FOR FURNACES.

Specification of Letters Patent. Patented Jan. 31, 1922; Application filed. September 18, 1919. Serial 1T0. 324,720.

(GRANTED UNDER THE PROVISIONS or THE ACT or MARCH 3, 1921, 41 screw. 1,, 1313.

T 0 all whom it may concern:

Be it known that I, HARRY STEHMANN, a subject of the German State, and resident of Berlin-Hohenshonhausen, Germany, have inventedcertain new and useful Improvements in Ash-Discharge Devices for Furnaces, (for which applications for at ents have been filed in Germany, May 3, 1917; Austria, June 11, 1919; Switzerland,

June 12, 1919, and'Norway, June 17, 1919,

and for which a patentwas granted in Germany January 10, 1921,) anddo hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in'the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to letters or figures of reference marked thereon, which form apart of this specification.

This invention .has for its object to 'provide for airtight closing of the discharge devices in use with shaft-furnaces and-the like, which are operated under forced draft by compressed air.

The trouble in these shaft-furnaces, operated under wind pressure, lies in the fact that large quantities of dust and grit are blown through the leaky-closing contrivances, such as dampers, registers and the like, into the working room beneath the discharge so as to render the atmosphere therein insupportable for the workmen; in addition the machines in the work room become covered with dust not'to' count the considerable loss of wind. That is why, in spite of heavy counter-weights, the known shutting devices in form'of registers and dampers have proved to be unsuitable in the operation of shaft furnaces. V 7

By the present invention the dust tight closing of the discharge pipes in use with shaft-furnaces is efi'ected and alljinconveniences and diiiiculties are overcome, thus ensuring a progress of extraordinary iln portance.

Back ofthis invention lies the thought of also rendering available the wind pressure itself in conjunction with the dust' for ensurin'g airtight sealing. This idea is realized by providing in the discharge pipe, ground-in closing contrivances, such .as conical valves which, until being compullonger occur.

sorily released, are pushed down into their seats by means of compressed air, while being in addition thereto hermetically covered over by a layer of outgoing material,blown.-there against." The whole of the upper valve surface becomes covered by a dense layer of dust, which to an increasing degree contributes to the complete sealing. This'is a new and characteristic means for. closing the discharge-pipes in shaft-furnaces, working with coarse, gritty and at the same time with finely pulverized materials. Thus the closures are securely pushed onto their seats by wind pressure and covered over by dust, whereas inuse with the registers, known theretofore, particularly when their sliding gridplates were worn outfthe wind increased'theleakage, blowing through the gaps large quantities of dust, which filled up the room beneath.

According to the present invention the mate- 'IliLl, which is to pass out, becomes lodged on the valve surfaces, thus automatically: 7

dampers, registers and thelike' can no The simplest form devised for this purpose s a valve dlsk, conically inserted or preferably ground-in nto adequate valve preferably arranged at the lower-extremities of such valves. These cleaning devices are slightly larger than the lower conical portion of the valve disk and spring back to their normal position after having skimmed over the valve seat, cleaning it at each opening and closing movement.

is preferred to build the conduit-pipe so that the several valve chambers form a se quence, arrangedjin steps and below each chamber is an inclined sliding surface or funnel. The device may, however, be so made that,1n case of the'closmg contrivances be- 85 seat, the surface whereof has a conical or ing opened an uninterrupted lower sliding or chute surface may be arrived at.

As a rule, two ground-in valves which are alternately raised or lowered, will do. The valve in the rear may be coupled up with a third shutting device, something like a simple damper, of known construction bearing against the extremity of a projecting inclined plane, on the conduit. The arrangement should preferably be so made that the damper shuts preparatory to the valve moving onto its'seat, in order to prevent the outgoing material from passing out prematurely. When the valves are opened they are withdrawn into valve receiving boxlike chambers arranged above the conduit.

The accompanying drawing illustrates diagrammatically a vertical section of a plant embodying the invention.

below the chambers in the conduit are outlet conical valve seats 9 and h, on which conical valve disks 5 and seat. The top faces of the valves 2' and 7c are inclined relative to their seats, the inclination being greater than the angle of repose of the material to be discharged for ensuring a free gliding down of the material resting thereon, while at the same time allowing the valves to be easily raised. The valves are securely pushed by the wind pressure onto their conical seats and besides they are hermetically covered over by a layer of outgoing material, blown there against. This has the effect of completely closing the chamber and preventing the dust from entering into the work room. The lower side of the closing device has arranged thereon a steel brush m for cleaning the valve seats.

In the form of construction as represented the several closures are interconnected in such a manner by any known devices, that the valve 70 and the damper 0 are opened and closed at the same time whereas the The preferred means for operating the valves comprises a rock-arm 0r lever a, pivoted on a standard 0. *The stems 2', 7c, of

the valves e and 70 respectively are pivotedly connected to the rock-arm'n on either side of the standard 0 The length of the valve stems is such that when the rock-arm is in a horizontal position the valve 2' is seated and the valve 70 is raised from its seat. The damper c has an operating arm 0 fixed thereto and this arm is connected by a link 10 to one arm of a pivoted bell-crank lever g, the other arm of the latter being connected by a link 1) to one end of the rock-arm n. lVhen the latter is rocked to raise the valve i from its seat the valve lowill be lowered onto the seat and the damper 0 swung against the offset 6.

The form of construction as shown does of course not exhaust the ways of carrying out the invention; it goes without saying that in its place any other type of closure can be chosen in which the closing appliances are automatically sealed by the effect of the wind pressure and by the outgoing material resting thereupon. Besides the -form of the shutting appliances and of pipe conduits can be arranged as required.

Thus by the means described any dust or gritty particles are prevented from entering the work room, and this means a stupendous progress in the construction of shaft-furnaces operating with wind pressures.

I claim:

1. The combination with a furnace having a grate, a chamber beneath said grate and means for supplying air .under pressure to said chamber; of a discharge chute for said chamber, a valve for closing said chute arranged to be held on its seat by the air pressure from said chamber, said valve having an upper face inclined relative to its seat when in closed position, the inclination of said face being greater than the angle of repose of the material tobe discharged,

whereby upon opening said valve the mawholly withdrawn from said chute into said chambers when opened or held to said seats by air pressure in said first mentioned chamher and chute.

3. The combination with a furnace having a grate, a chamber beneath said grate, means for supplying air under pressure to said chamber and means for closing the bottom of said chamber; of an inclined chute'extending from said closing means, two valves arranged and operatively connected for alternately closing and opening said chute, the lowermost valve positively connected to said closing means and simultaneously oper- 1,405,0ae g ated therewith, said valves held to their seats by the air pressure in the first mentioned chamber and chute.

4. The combination with a furnace having a grate, a chamber beneath said grate, a flap damper for closing the bottom of said chamher, and means to supply air under pressure to said chamber; of an inclined chute extending from said damper and chamber, valve chambers extending from said chute, conical valve seats in the chute below said valve chambers, valves arranged to be withdrawn into said valve chambers when opened and having surfaces on their tops inclined relatively to their seats when closed, and vali e seat cleaning devices on the bottoms of said valves, the lowermost valve arranged and connected to operate simultaneously with said flap damper.

5. The combination with a furnace having a grate, a chamber beneath said grate and means for supplying air under pressure to said chamber; of a discharge chute for said chamber, a valve for closing said chute having an upper face inclined relatively to its seat and directed toward said chamber, said face operating to hold the valve on its seat when closed by the air pressure and the material in the chute acting thereon.

6. The combination with a furnace having a grate, a chamber beneath said grate and means for supplyin air under pressure to said chamber; of a discharge chute for said chamber, a valve for closing said chute arranged to be held on its seat by the air pressure from said chamber, its own weight and the weight of the material.

In testimony that I claim the foregoing as my invention, I have signed my name in presence of two subscribing witnesses.

- HARRY STEHMANN. Witnesses: V

JULIN PRINTSE, JERREY MATTHIES. 

